Hibernating mammals may lose up to 30 percent of their
brain’s connections during hibernation, but the connections
are restored come spring
Cold-shock proteins, which exist to help your body survive
low temperatures, appear necessary to help restore the lost
connections
Sleep and sleep loss modify the expression of several genes
and gene products that may be important for synaptic
plasticity and memory enhancement in humans
By Dr. Mercola
When animals hibernate, their body temperatures drop and their
metabolism slows significantly (in some cases to just 2 percent of
normal). In this state of virtual suspended animation, the animals’
brains show signs of changes akin to early-stage Alzheimer’s, and
some even lose their memories.
Specifically, when animals hibernate the cooling induces a loss
in synapses, which are the connections between brain cells. Synapses
are also lost in the early stages of certain neurodegenerative
diseases, including Alzheimer’s disease.
In humans the early loss of synapses typically progresses to the
point that whole brain cells begin to die – and memories go along
with them. Hibernating mammals may lose up to 30 percent of their
brain’s connections during hibernation.
The connections are restored come spring, which has
caught the attention of researchers wondering if restoring lost
memories in humans might someday be possible.
Cold-Shock Proteins May Help Prevent Memory Loss
A new study published in Nature unraveled more clues
about how hibernation might give clues to preventing dementia.1
When mice were artificially cooled, a number of cold-shock proteins,
including RNA-binding protein (RBM3), were induced in the brain – a
process that also occurs during hibernation.
Cold-shock proteins exist to help your body survive low
temperatures (they’re at the other end of the spectrum from
heat-shock proteins, which are induced by heat to help protect
your body from heat stress).
All of the mice lost synapses during the study, but while older
mice were not able to reestablish them when warmed up, young mice
with neurodegenerative diseases regained their lost connections.
The difference was attributed to levels of RBM3, which “soared”
in the young mice during cooling but not in the older mice. The
researchers believe enhancing cold-shock pathways could offer
potential protective therapies for neurodegenerative diseases, but
they’re looking into ways of doing this other than cooling your body
(which wouldn’t be practical for chronic treatment).
Interestingly, rapidly cooling the body has been suggested as a
plausible medical treatment for a variety of conditions, from
traumatic injuries to preventing brain damage from strokes.
Sleeping May Help You Enhance Your Memory
Research from Harvard indicates that people are 33 percent more
likely to infer connections among distantly related ideas after
sleeping,2
but few realize that their performance has actually improved.
Sleep is also known to enhance your memories and help you
"practice" and improve your performance of challenging skills. In
fact, a single night of sleeping only 4 to 6 hours can impact your
ability to think clearly the next day.
The process of brain growth, or
neuroplasticity, is believed to underlie your brain's capacity
to control behavior, including learning and memory. Plasticity
occurs when neurons are stimulated by events, or information, from
the environment. However, sleep and sleep loss modify the expression
of several genes and gene products that may be important for
synaptic plasticity.
Furthermore, certain forms of long-term potentiation, a neural
process associated with the laying down of learning and memory, can
be elicited in sleep, suggesting synaptic connections are
strengthened while you slumber.
To be clear, sleeping is not the same as
hibernating. Hibernation would be more akin to resting in a coma
than sleep, and research shows that animals often show signs of
sleep deprivation upon waking from hibernation. As reported by
Popular Science:3
“When a mammal is in torpor [a short period of
hibernation], it gets less rapid eye movement (REM) sleep and
less slow wave sleep, because good sleep involves some
physiological processes that require warmer body temperatures.
Animals sleep a lot when they emerge from torpor, with brain
activity patterns demonstrating signs of sleep deprivation.”
So while hibernation may hold clues to restoring memories related
to lost synapses, hibernation does not appear to give the body the
benefits of proper sleep, which are separate and equally important.
Naps Help Babies and Adults Retain Memories
There’s a reason why babies nap and, perhaps, why you should,
too. Research shows that naps can give a boost to babies'
brainpower. Specifically, infants who slept in between learning and
testing sessions had a better ability to recognize patterns in new
information, which signals an important change in memory that plays
an essential role in cognitive development.4
New research also shows that napping for 30 minutes or more
within 4 hours of learning a new behavior helps infants retain their
memories.5
The results suggest that infants rely on frequent naps to help form
long-term memories, and there's reason to believe this holds true
for adults, too.
Even among adults, a mid-day nap was found to dramatically boost
and restore brainpower.6
Dr. Rubin Naiman -- a clinical psychologist, author, teacher,
and the leader in integrative medicine approaches to sleep and
dreams – believes that humans are biologically programmed to nap, so
if you feel the urge to nod off in the afternoon, don’t fight it.
The “ideal” nap time appears to be around 20 minutes (any longer
and you’ll enter the deeper stages of sleep and may feel groggy when
you wake up). According to the National Sleep Foundation:7
“Sleeping for a short time can make you more alert and
energetic--this might be critical to your work or school
productivity, or to your ability to take care of a child during
the day. Most people feel refreshed after a nap that lasts
approximately 20 minutes.”
At Nighttime You Should Strive for Uninterrupted Sleep
While many animals engage in torpor, which is basically shorter
periods of interrupted hibernation, humans need uninterrupted
sleep to function properly. It makes sense that interruptions
to your sleep would result in much the same damage as lack of sleep,
because sleep occurs in phases.
Ideally, you should progress from slow-wave sleep back up to REM
sleep in 60- to 90-minute cycles. Any interruptions to this make
your body start over in a sense, which means you might never reach
the most restorative, deeper phases of sleep.
You might as well not be sleeping at all, which is likely one
reason why lack of sleep and interrupted sleep result in such
similar damage. In a healthy night’s sleep, you should progress
through the following sleep stages (though not necessarily in this
order):8
Stage One, when you’re preparing to drift off
Stage Two, during which your brain wave activity becomes
rapid and rhythmic while your body temperature drops and heart
rate slows
Stage Three, when deep slow brain waves emerge (this is a
transition from light sleep to deep sleep)
Stage Four, also known as delta sleep, this is a deep sleep
stage
Stage Five, or rapid eye movement (REM) sleep, is when most
dreaming occurs
“Sleep does not progress through all of these stages in
sequence, however. Sleep begins in Stage One and progresses into
stages 2, 3, and 4. Then, after Stage Four sleep, Stages Three,
then Two are repeated before going into REM sleep.
Once REM is over, we usually return to Stage Two sleep. Sleep
cycles through these stages approximately 4 or 5 times
throughout the night. We typically enter REM approximately 90
minutes after falling asleep. The first cycle of REM often lasts
only a short amount of time, but each cycle becomes longer.
This is why we need long periods of sleep each night as
most of the REM sleep occurs in the hours before awakening. If
we get short periods of sleep, we can’t really get through the
stages we need to heal and stay healthy. REM can last up to an
hour as our sleep progresses. In case you are wondering, if you
feel like a dream is taking a long period of time, it really is.
Contrary to what was once believed, dreams take as long as they
actually seem.”
Keep Your Phone and Tablet Out of Your Bedroom
One of the greatest plights of modern-day sleep is the
introduction of light-emitting electronic devices to the bedroom.
Research shows that 90 percent of Americans use an electronic device
within an hour of going to bed, and this is associated with poor
sleep.10
A new study also compared the use of an iPad for 4 hours before bed
(for five consecutive nights) to reading a print book for the same
period.11
There were significant biological effects of iPad use before bed,
including:12
Reduced secretion of melatonin, a hormone that induces
sleepiness
Delayed circadian rhythm of more than an hour
Feeling less sleepy before bedtime
Feeling sleepier and less alert the following morning, even
after 8 hours of sleep
Spending less time in REM sleep
One of the study’s authors noted: "We found the body's
natural circadian rhythms were interrupted by the short-wavelength
enriched light, otherwise known as blue light, from these electronic
devices.” The blue light emitted from electronics such as cell
phones, tablets, TVs and computers suppresses your
melatonin production, thereby preventing you from feeling
sleepy. What you may not realize is that even if you don't feel
sleepy, you need sleep. You've simply artificially
disrupted your body clock; you have not in any way altered your
body's biological needs. Last year I
interviewed Dan Pardi on the topic of how to get restorative,
health-promoting sleep.
Pardi is a researcher who works with the Behavioral Sciences
Department at Stanford University and the Departments of Neurology
and Endocrinology at Leiden University in the Netherlands.In
addition to avoiding blue light at night, Pardi recommends getting
at least 30-60 minutes of outdoor light exposure during daylight
hours in order to "anchor" your master clock rhythm. The ideal time
to go outdoors is right around solar noon but any time during
daylight hours is useful. Once the sun has set, the converse
applies. After sunset you want to avoid light as much as
possible in order for your body to secrete melatonin, which helps
you feel sleepy.
You Probably Need to Go to Bed Earlier Than You Think
You may be surprised at how little sleep you’re actually getting.
If you go to bed at 10 pm and get out of bed at 7 am, you might say
you’ve slept for nine hours. In reality, you probably spent at least
15-30 minutes falling asleep and may have woken during the night one
or more times. With the advent of fitness-tracking wristbands such
as Jawbone’s UP, however, it’s now possible to track your actual
sleep time. When I first started using a fitness tracker, I was
striving to get 8 hours of sleep, but my Jawbone UP typically
recorded me at 7.5 to 7.75.
I have been using an UP tracker for the last six months and just
the last month have finally been able to restructure my schedule so
that I am getting close to 9 hours of sleep. Quite a contrast from
when I was seeing patients, as it would typically be far closer to
an unhealthy 5 hours or less. I have since increased my sleep time,
not just time in bed, but total sleep time to over 8 hours per day.
The fitness tracker helped me realize that unless I am asleep, not
just in bed, but asleep by 10 pm I won’t get my 8 hours. Gradually I
have been able to get this down to 9:30 pm.
The tracker also differentiates between sound and light sleep,
and through trial and error, I was able to use the device to figure
out I can get 6 hours of deep sleep if I maintain my air temperature
around 66-68 degrees F with only a light sheet on. If it is much
warmer or I use a blanket, my sound sleep can drop to 2-3. Pardi
recently shared how having a baby has helped to improve his
overall sleep because it got him in the habit of going to sleep
earlier, and importantly, getting into bed prior to feeling sleepy.
He explains:13
“Yes, having a baby has improved my overall sleep
practice. Because of my son, we wind our evening down earlier
than normal in order to get him to bed at a good time for him.
Since we must initiate these activities earlier than what we
would do for ourselves, it has gotten us into the habit of
thinking of sleep earlier than normal.
Specifically, I get into bed earlier than I used to. Now,
I will read my kindle, with dim backlight, in a room with
amber-toned environmental light, and as soon as the urge for
sleep strikes, all I have to do is put down the book. Most
people, on the other hand, initiate their going-to-bed ‘program’
once they start to feel sleepy.
So, instead of being able to actually allow sleep to
happen at this instance, you need to do a list of things – like
brush your teeth, move yourself into bed, etc. – before you’re
able to close your eyes. Because you’re sleepy, you’re likely to
move slowly to accomplish this list, and it’s easy to see how
maintaining this latter pattern cuts into total sleep time; even
30 minutes of less sleep per night on a regular basis matters!
You don’t have to have a young child to benefit from this
lesson: get into bed prior to when you want to be
sleeping so you can give into the impulse as soon as it hits.”
Longing for a Good Night’s Sleep? Try These Tips
To achieve more restful, restorative sleep, I suggest you read
through my full set of
33 healthy sleep guidelines for all of the details, but to
start, consider implementing the following changes:
Avoid watching TV or using your computer in the
evening,at least an hour or so before going to
bed. These devices emit blue light, which tricks your
brain into thinking it's still daytime. Normally, your brain
starts secreting melatonin between 9 pm and 10 pm, and these
devices emit light that may stifle that process.
Even the American Medical Association now states:14“…nighttime
electric light can disrupt circadian rhythms in humans and
documents the rapidly advancing understanding from basic science
of how disruption of circadian rhythmicity affects aspects of
physiology with direct links to human health, such as cell cycle
regulation, DNA damage response, and metabolism.”
Make sure you get BRIGHT sun exposure regularly.
Your pineal gland produces melatonin roughly in approximation to
the contrast of bright sun exposure in the day and complete
darkness at night. If you are in darkness all day long, it can't
appreciate the difference and will not optimize your melatonin
production.
Sleep in complete darkness, or as close to it as
possible. The slightest bit of light in your bedroom
can disrupt your body’s clock and your pineal gland's melatonin
production. Even the tiniest glow from your clock radio could be
interfering with your sleep, so cover your radio up at night or
get rid of it altogether. Move all electrical devices at least
three feet away from your bed. You may want to cover your
windows with drapes or blackout shades. If this isn’t possible,
wear an eye mask.
Install a low-wattage yellow, orange, or red light
bulb if you need a source of light for navigation at night.
Light in these bandwidths does not shut down melatonin
production in the way that white and blue bandwidth light does.
Salt lamps are handy for this purpose. You can also download a
free application called F.lux that automatically dims your
monitor or screens.15
Keep the temperature in your bedroom no higher than
70 degrees F. Many people keep their homes too warm
(particularly their upstairs bedrooms). Studies show that the
optimal
room temperature for sleep is between 60 to 68 degrees F.
Take a hot bath 90 to 120 minutes before bedtime.
This increases your core body temperature, and when you get out
of the bath it abruptly drops, signaling your body that you are
ready to sleep.
Avoid using loud alarm clocks. Being jolted
awake each morning can be very stressful. If you are regularly
getting enough sleep, you might not even need an alarm.
Get some sun in the morning, if possible.
Your circadian system needs bright light to reset itself. Ten to
15 minutes of morning sunlight will send a strong message to
your internal clock that day has arrived, making it less likely
to be confused by weaker light signals during the night. More
sunlight exposure is required as you age.
Be mindful of electromagnetic fields (EMFs) in your
bedroom. EMFs can disrupt your pineal gland and its
melatonin production, and may have other negative biological
effects as well. A gauss meter is required if you want to
measure
EMF levels in various areas of your home. Ideally, you
should turn off any wireless router while you are sleeping. You
don’t need the Internet on when you are asleep.
Copyright 1997- 2015 Dr. Joseph Mercola. All Rights Reserved.